1. Field of the Invention
The present invention relates to an electron beam generating apparatus and an optical sampling apparatus for sampling the waveform of an electron beam generated by the electron beam generating apparatus.
2. Description of the Related Art
JP-A-H4-297836 and JP-A-2003-57118 disclose an optical sampling.
JP-A-H4-297836 discloses an apparatus that includes an electron tube having sensitivity with which one photoelectron is released in response to absorption of one photon within a predetermined wavelength range, and a pulse light source for generating sampling light pulses in a predetermined wavelength out of the predetermined wavelength range. As soon as light to be measured and a sampling light pulse enter together onto a photoelectric surface of the electron tube, one photoelectron is released from the photoelectric surface in accordance with the multiphoton absorption
JP-A-2003-57118 discloses an apparatus that includes a photo-detector for converting an incident high-frequency light signal to be measured, into a high-frequency electric signal, a photoconductive switch for receiving a light pulse signal, and an electrode connecting the photo-detector and the photoconductive switch with each other, so as to sample the high-frequency electric signal by means of the light pulse signal incident on the photoconductive switch, and output an output signal.
In addition, the electrode is designed so that the high-frequency light signal to be measured and the light pulse signal have no interference with each other, and so that the size of the electrode is shorter than the size long enough to produce a waveform distortion in the output signal due to a reflected wave in the electrode.
FIG. 1 is a main portion configuration view of an optical sampling apparatus generally used in the prior art.
In FIG. 1, an optical signal 1 is converted into an electric signal by a photoelectric conversion element 2 such as a photo-detector, and the electric signal is sampled by an electrical sampler 3, and displayed on an oscilloscope 4.